I think the acquisition of Rakell would be precisely with the cap in mind, perhaps due to having made a big UFA splash like signing Pietrangelo.
Here is what the Colorado roster would look like in that context.
As such, the cap would be just as valuable to Colorado as to other teams. But yeah, in a vacuum Colorado probably wouldn't value Rakell's low cap hit quite as highly as the likes of Tampa, Toronto, etc.
Whatever the case, I'm surprised that you wouldn't accept that offer. Looking at Anaheim's roster a young RHD with top 4 (or even top pairing) potential seems like a big need, and it's unlikely that you'd get a better offer than that.
Though I think Timmins + 1st is a generous offer, for the sake of argument, would an additional B prospect or mid-round pick would get it done for you?